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Biomedical subjects

M Quinn

Publications and source records attributed to M Quinn.

At least 127 records · Page 7Linked to original sources
PubMed1996

Potential problem when using the new lower-prime hollow-fibre membrane oxygenators with uncoated stainless steel heat exchangers.

A prospective study was conducted to evaluate the trans-oxygenator pressure gradient across three different hollow-fibre membrane oxygenators during routine cardiopulmonary bypass (CPB). Sixty consecutive open-heart surgery patients were randomly divided into three groups each receiving a different model of membrane oxygenator. Inlet and outlet pressures, as well as patients' pressures, blood flow, revolutions per minute and tympanic membrane temperature were recorded every 15 min during CPB. Within the study groups, there were subsets of patients who exhibited high trans-oxygenator pressures. Although most of these episodes were transient and resolved over a period of time, there were several cases during which the high trans-membrane pressures persisted, resulting in decreasing oxygenator performance. In one such case, oxygenator change-out was required. After extensive analysis and review, the only similarities or correlation that could be made were with the marriage of the newer lower-prime hollow-fibre membrane oxygenators (with corresponding narrow blood path) and the integral uncoated stainless steel heat exchangers. Further study needs to be performed to pinpoint the mechanism and pathophysiology that are involved in this phenomenon.

Biocompatible Materials↗
PubMed1995

Changes in incidence of and mortality from breast cancer in England and Wales since introduction of screening. United Kingdom Association of Cancer Registries.

OBJECTIVE: To assess the impact of the NHS breast screening programme on the incidence of and mortality from breast cancer. DESIGN: Comparison of age specific incidence and mortality before and after the introduction of screening in the late 1980s. SETTING: England and Wales. SUBJECTS: Women aged over 30 years. RESULTS: In 1992 the age standardised incidence of breast cancer was 40% higher than in 1979. After the introduction of screening in 1988 recorded incidence rates rose steeply in the screened age group (50-64 year olds) but not in others. In 1992 the rates levelled off at about 25% higher than in 1987. Total mortality from breast cancer has increased steadily since the 1950s; the rates increased earlier in the younger age groups. By the mid-1980s rates had begun to fall in the younger age groups; but total mortality was still among the highest in the world. Age standardised mortality in the 55-69 age group changed little during the first three years of screening but then fell steeply and in 1994 was 12% lower than in 1987. CONCLUSIONS: Since the introduction of screening there have been pronounced increases in recorded incidence in the screened age group. Cancer registries have an essential role in assessing screening programmes and cancer services. The steep decrease in mortality in 55-69 year olds which began three years after screening started is unlikely to be due to screening. The widespread adoption of treatment with tamoxifen during this period may be important. With the reduction in mortality already observed and the expected additional benefits from screening, the Health of the Nation target should be achieved.

Age Factors↗
PubMed1995

Reproductive and other factors and risk of epithelial ovarian cancer: an Australian case-control study. Survey of Women's Health Study Group.

Of the few factors known to be associated with epithelial ovarian cancer, the most consistently observed relate to women's reproductive function, although even here uncertainties remain. We have undertaken a case-control study involving personal interviews with over 1,600 women, the largest of its kind to date, to investigate further the associations between women's reproductive histories and other factors and the development of ovarian cancer. Cases were drawn from women diagnosed with epithelial ovarian cancer in 3 Australian states, Queensland, New South Wales and Victoria, between August 1990 and December 1993, and controls were drawn at random from the electoral roll, stratified by age and geographic region. Trained interviewers administered standard questionnaires to obtain detailed information about women's reproductive and contraceptive histories and other factors of interest, such as smoking and family history of ovarian or other cancer. Findings were based on data from 824 cases and 860 controls and confirmed the reduced risk of ovarian cancer associated with increasing parity and duration of use of the oral contraceptive pill (OCP), hysterectomy and tubal ligation. The strongest association of all was seen with use of the OCP for 10 years or more. An inverse association between ovarian cancer and age at first birth was observed, but this was not statistically significant. There were no associations between development of ovarian cancer and number of incomplete pregnancies, use of hormone replacement therapy or menstrual history. Among other factors considered, education after leaving school was negatively associated and high body mass index, family history of ovarian cancer, use of talc in the abdominal or perineal region and smoking were positively associated with occurrence of ovarian cancer.

Adolescent↗
PubMed1995

Glycosylated hemoglobin and the risk of microalbuminuria in patients with insulin-dependent diabetes mellitus.

BACKGROUND: The risk of microalbuminuria in patients with insulin-dependent diabetes mellitus (IDDM) is thought to depend on the degree of hyperglycemia, but the relation between the degree of hyperglycemia and urinary albumin excretion has not been defined. METHODS: We measured urinary albumin excretion in three random urine samples obtained at least one month apart from 1613 patients with IDDM. Microalbuminuria or overt albuminuria was considered to be present if the ratio of albumin (in micrograms) to creatinine (in milligrams) was 17 to 299 or > or = 300, respectively, for men and 25 to 299 or > or = 300, respectively, for women. Measurements of glycosylated hemoglobin (hemoglobin A1) obtained up to four years before the urine testing were used as an index of hyperglycemia. Twelve percent of the patients had overt albuminuria and were excluded from subsequent analyses. RESULTS: The prevalence of microalbuminuria was 18 percent in patients with IDDM. It increased with increasing postpubertal duration of diabetes and, within each six-year interval of disease duration, it increased nonlinearly with the hemoglobin A1 value. For hemoglobin A1 values below 10.1 percent, the slope of the relation was almost flat, whereas for values above 10.1 percent, the prevalence of microalbuminuria rose steeply (P < 0.001). For example, as the hemoglobin A1 value increased from 8.1 to 10.1 percent, the odds of microalbuminuria increased by a factor of 1.3, but as the value increased from 10.1 to 12.1 percent, the odds were increased by a factor of 2.4. CONCLUSIONS: The risk of microalbuminuria in patients with IDDM increases abruptly above a hemoglobin A1 value of 10.1 percent (equivalent to a hemoglobin A1c value of 8.1 percent), suggesting that efforts to reduce the frequency of diabetic nephropathy should be focused on reducing hemoglobin A1 values that are above this threshold.

Adolescent↗
PubMed1995

Alterations in diaphragm EMG activity during opiate-induced respiratory depression.

While opiate-induced increases in thoracic muscle tone may contribute to impaired ventilation during opiate anesthesia, the effects of high-dose opiates on diaphragm muscle activity have not been elucidated. The effects of the opiate agonist alfentanil (ALF, 500 micrograms/kg subcutaneously) on diaphragm (DIA) and intercostal (IC) electromyographic (EMG) activity in spontaneously ventilating adult rats were studied. EMG segments corresponding to inspiration and expiration were selected using an impedance plethysmographic respiratory waveform. Total EMG activity over a respiratory cycle was significantly greater in the DIA than in the IC. ALF produced a decrease in inspiratory and an increase in expiratory DIA EMG activity. These changes in diaphragm function following ALF were accompanied by significant respiratory depression. The effects of the alpha-2 agonist dexmedetomidine on ALF-induced changes in diaphragm and intercostal EMG activity were also examined. While dexmedetomidine alone had minimal effects on DIA activity, it significantly attenuated the ALF-induced increase in expiratory DIA EMG. The potential etiology and implications of these opiate-induced changes in diaphragm muscle function are discussed.

Alfentanil↗
PubMed1995

Reducing surgical length of stay: quantifying the impact.

Length-of-stay (LOS) reduction is a strategy encouraged at all levels of health care to manage within a resource limited environment. However, few organizations have attempted to quantitatively understand the impact of reducing LOS. This study examines the relationship between reducing LOS and cost through a retrospective, medical records analysis of three surgical procedures (appendectomy, cholecystectomy and caesarean section) at an Ontario community hospital Department of Surgery. Hypotheses are presented and a methodology is described. The results are discussed with a focus on the factors that hospitals, administrators and physicians might consider in a LOS reduction program.

Adolescent↗
PubMed1995

Korotkoff's sounds in pregnancy.

Korotkoff described the sequence of vascular sounds heard with a stethoscope over the brachial artery during deflation of a pneumatic cuff. The initial sounds are produced by vibrations of the vessel wall, although the sequence of vascular sounds has frequently been ascribed to 'turbulence' of flow in the vessel. This study has been performed to determine the relationship between the vascular sounds (Korotkoff I-V) produced during blood pressure cuff deflation and specific changes in the brachial artery waveform. Ten nulliparous women admitted to hospital in the third trimester of pregnancy have been studied by means of concurrent Doppler ultrasound and phonocardiography. Changes in the brachial artery waveform during blood pressure cuff deflation were recorded using Doppler ultrasound (7.5 MHz) with concurrent objective demonstration of phases I-V of the vascular sounds using a phonocardiography microphone. Characteristic features of the brachial artery waveform were associated with phases I-IV of the vascular sounds in all patients (10/10). No consistent features of the brachial artery waveform were associated with phase V of the vascular sounds. Phases I-IV of the vascular sounds are associated with specific changes in the pattern and direction of flow within the brachial artery in normotensive primigravid women. The vascular sounds produced by vibration of the vessel wall are modulated by changes in blood flow to produce the characteristic sequence of vascular sounds detected with a stethoscope during blood pressure cuff deflation.

Adolescent↗
PubMed1995

A simple method for the propagation of cervical lymphocytes.

Local immune function is most likely a key influence in the establishment of human papillomavirus infections and its subsequent disease. Unfortunately, little information is known about local cervical immunity, and even less is known about human papillomavirus immunoreactivity. In addition, studies of local immunoreactivity have been hampered by the technical difficulty in obtaining cervical lymphocytes. The objective of the present study was to develop a simple method for the propagation of cervical lymphocytes from biopsy-size specimens. Cervical tissue was obtained from women undergoing a hysterectomy. Cervical samples measuring approximately 3 by 5 by 2 mm were minced and divided into two portions. One portion was digested by standard digestion methods and density gradient lymphocyte separation. The sample was then immunocharacterized for CD4 and CD8 cells by flow cytometry. The other portion was minced into 1-mm3 sections, and each section was placed into a separate well with tissue culture medium and interleukin-2. Lymphocyte counts and immunophenotypic analysis were performed after 18 to 20 days in culture. After 18 to 20 days in culture, the analysis demonstrated that this method of direct lymphocyte culture from a biopsy specimen yielded approximately 1 x 10(6) to 5 x 10(6) lymphocytes. Immunophenotypic studies of the digested sample at day 0 revealed CD4-to-CD8 ratios of between 0.7:1 and 3.5:1, and at days 18 to 20 they revealed ratios of between 2.3:1 and 98:1. In summary, we developed a simple technique for propagating cervical lymphocytes from small tissue samples for the study of the local immune response. Studies are under way to optimize lymphocyte growth and to preserve CD8 populations.

Adolescent↗
PubMed1995

Nellcor Stat Cap differentiates oesophageal from tracheal intubation.

A trial of the Nellcor Stat Cap, which detects exhaled carbon dioxide, as an aid to determining whether endotracheal tubes are placed in the oesophagus or the trachea, was carried out in the neonatal unit of this hospital. Twenty five neonates, with a mean (range) gestational age of 33 (24-42) weeks and a mean (range) birthweight of 2.17 (0.54-4.1) kg were studied over two months. These babies underwent a total of 58 intubations and 20 suspected self-extubations. The Nellcor Stat Cap was easy to use. It confirmed clinical findings on 20/20 occasions when the endotracheal tube was in the oesophagus and on 57/58 (98%) occasions when it was in the trachea. On 14/78 (19%) occasions the machine provided helpful additional information in reaching a decision on the adequacy of tube placement. Failure to detect rapidly accidental oesophageal intubation or unintentional tracheal extubation can result in rapid deterioration of the condition of ventilated newborns. The machine is a valuable aid to intubation and rapid diagnosis of self-extubation.

Breath Tests↗
PubMed1994

A prospective study of inhibin in granulosa cell tumors of the ovary.

Elevated preoperative serum inhibin concentrations have been reported in patients with granulosa cell tumor of the ovary. The aim of this study was to determine if elevations in serum inhibin predated clinical recurrence in patients with a diagnosis of granulosa cell tumor. Twenty-seven consecutive patients with granulosa cell tumor were followed prospectively to assess the relationship between serum inhibin concentrations and disease status. The serum inhibin concentrations in normal postmenopausal women were < 77-130 U/liter. In patients with granulosa cell tumor at initial surgery, mean inhibin concentrations preoperatively were 2831 U/liter in 4 postmenopausal subjects (range 2130-3323 U/liter) and 3680 U/liter in each of 2 premenopausal women. In 5 postmenopausal subjects with a histological diagnosis of granulosa cell tumor who underwent secondary surgery because of a recurrent palpable mass, mean inhibin concentrations were 4216 U/liter (range 2672-7360). In 3 patients with known or suspected residual disease despite a secondary debulking operation the serum inhibin concentrations were 475, 1000, and 2541 U/liter. In 13 subjects who were clinically disease free with a previous diagnosis of granulosa cell tumor, serum inhibin concentrations remained within the normal range for reproductive status. We conclude: (1) Preoperative serum inhibin concentrations are typically elevated sevenfold above the normal premenopausal follicular phase levels in women with granulosa cell tumor; (2) after surgery, serum inhibin levels may become elevated up to 2 years before further surgery is undertaken; and (3) serum inhibin concentrations appear to be a valuable tumor marker for the diagnosis of primary or recurrent granulosa cell tumor.

Adult↗
PubMed1994

Automated blood pressure measurement devices: a potential source of morbidity in preeclampsia?

OBJECTIVE: The purpose was to compare auscultatory and oscillometric techniques in the determination of maternal blood pressure in normotensive primigravid patients and primigravid patients with proteinuric preeclampsia (blood pressure > 140/90 on two occasions and proteinuria > 0.5 gm/L). STUDY DESIGN: A prospective comparison of systolic and diastolic blood pressure was made with an automated device using oscillometric principles and two observers using a double-headed stethoscope to determine auscultatory observations (phase I and phase IV of the vascular sounds) in normotensive primigravid patients (N = 40) and primigravid patients with proteinuric hypertension (N = 17). RESULTS: In patients with proteinuric preeclampsia the mean differences between auscultatory (phase I and phase IV) and oscillometric observations were 5.4 mm Hg (SEM 1.4 mm, p < 0.05) and 14.8 mm Hg (SEM 2.9 mm, p < 0.01) for systolic and diastolic observations, respectively. In normotensive patients the mean differences between auscultatory (phase I and phase IV) and oscillometric observations were 2.4 mm Hg (SEM 0.9 mm, p not significant) and 7.5 mm Hg (SEM 1.9 mm, p < 0.01) for systolic and diastolic observations, respectively. CONCLUSION: Automated devices using oscillometric principles "underrecord" systolic and diastolic blood pressure compared with auscultatory observations (phase I and phase IV) in patients with proteinuric preeclampsia. In some cases the difference between observations exceeds 30 mm Hg.

Adult↗
PubMed1994

EMACO in high risk gestational trophoblast disease--the Australian experience. Gestational Trophoblast Subcommittee, Clinical Oncological Society of Australia.

Sixty-five patients with high-risk trophoblast disease have been treated with the EMACO combination split regimen therapy in the 10 year period, 1981 to 1990. Four patients died but the remaining 61 (94%) remain free of disease up to 10 years later. Toxicity was manageable in most cases with minimal delay in treatment from myelosuppression. EMACO is a well tolerated regimen with a high cure rate in patients with high-risk gestational trophoblast disease (GTD).

Adolescent↗
PubMed1993

Elevated serum inhibin concentrations in postmenopausal women with ovarian tumors.

BACKGROUND: Inhibin is an ovarian hormone that inhibits the secretion of follicle-stimulating hormone (FSH) by the anterior pituitary gland. Women with granulosa-cell tumors of the ovary have elevated serum inhibin concentrations, but whether the concentrations are increased in women with other ovarian tumors is unknown. METHODS: We measured serum inhibin and FSH concentrations before surgery in 212 postmenopausal women with suspected ovarian cancer and after surgery in 210 of them. RESULTS: Eighteen of the 22 women (82 percent) with mucinous carcinomas (mucinous cystadenocarcinomas and mucinous borderline cystic tumors) of the ovary had elevated serum inhibin concentrations, whereas only 9 of the 53 women (17 percent) with serous carcinomas (serous cystadenocarcinomas and serous borderline cystic tumors) had elevated levels. Serum inhibin concentrations were also elevated in 2 of 12 women (17 percent) with clear-cell carcinomas, 4 of 26 women (15 percent) with undifferentiated carcinomas, 3 of 3 women (100 percent) with granulosa-cell tumors, and 5 of 27 women (19 percent) with other ovarian cancers. The serum concentrations of inhibin were increased in 2 of 28 women (7 percent) with nonovarian pelvic cancers and 11 of 41 women (27 percent) with benign ovarian diseases. All women but one with initially elevated serum inhibin concentrations had low values one week after surgery. Serum inhibin concentrations correlated negatively with serum FSH concentrations (P = 0.05) in women with granulosa-cell tumors but not in women with other tumors, suggesting that the inhibin secreted by tumors in the latter group has decreased biologic activity. CONCLUSIONS: Serum inhibin concentrations are elevated in most postmenopausal women with mucinous carcinomas of the ovary and in some women with other types of epithelial ovarian tumors. The concentrations fall after tumor removal.

Adenocarcinoma, Clear Cell↗